Double Z-scheme Ag2CrO4/Bi2O3–KBi6O9Br nanophotocatalysts designed via microwave-assisted combustion-precipitation method for degrading toxic organic dyes.

This study introduces novel double Z-scheme Ag 2 CrO 4 /Bi 2 O 3 –KBi 6 O 9 Br nanophotocatalysts for effectively degrading organic dyes, namely Crystal Violet, Acid Orange 7, Rhodamine B, and Eosin Y, from contaminated wastewater. The photocatalysts were thoroughly characterized using advanced techniques, including X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDX-Dot Mapping), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), Diffuse Reflectance Spectroscopy (DRS), and Photoluminescence (PL). XRD confirmed the formation of desired crystalline phases without impurities. FESEM and TEM observations revealed the unique morphology of Bi 2 O 3 –KBi 6 O 9 Br, with distributed Ag 2 CrO 4 nanoparticles on the surface, as confirmed by EDX-dot mapping. BET-BJH analyses indicated a specific surface area of 7.33 m2/g, including meso and macro pores with an average diameter of 10 nm and a total pore volume of 0.018 cm3/g for Ag 2 CrO 4 (25%)/Bi 2 O 3 –KBi 6 O 9 Br sample. DRS revealed notable shifts in absorption edges, suggesting the formation of a heterojunction, and PL analysis indicated a reduced charge carrier recombination rate, further enhancing the photocatalyst's efficacy. In a series of photocatalytic experiments lasting 240 min, using 1 g/L of Ag 2 CrO 4 (25%)/Bi 2 O 3 –KBi 6 O 9 Br, remarkable degradation efficiencies of 95.1%, 94.2%, 98.0%, and 89.6% were achieved for Crystal Violet, Acid Orange 7, Rhodamine B, and Eosin Y, respectively, at an initial concentration of 10 mg/L. The nanophotocatalyst also showed favourable stability after five consecutive reuses. Overall, the double Z-scheme heterostructure in the composite significantly improved the sample's properties and photocatalytic performance, making it highly effective in removing various organic dyes from wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]